<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .fa{width: 400px;
        height: 400px;
        background-color: yellow;
        position: relative;}
        .son{
            width: 200px;
            height: 200px;
            background-color: teal;
            position: absolute;
            top: 100px;
            left: 100px;
        }

    </style>
</head>
<body><div class="fa">
    <div class="son">
    </div>
</div>
    
</body>
</html>